Ralph E. Moon, Ph.D. CHMM, CIAQP, MRSA GHD, Inc. [email protected] 813-971-3882 (office) 813-257-0838 (desk)

Understanding Moisture Penetration of the Drainage Plane: A Building Science Principle Use Font size 40

2019 IAQA Annual Meeting Why is this relevant to the IAQ professional? • The fundamental role of any structure is to keep water out • The drainage plane constitutes the elements that protect the structure and prevent water penetration • Understanding how water penetrates a structure is necessary to identify why indoor air quality may be impaired 2019 IAQA Annual Meeting The Four Basic Rules of Water Damage

• Porous materials “suck” via capillary action • Water vapor diffuses from a higher to a lower concentration gradient • Air carrying water vapor moves from high pressure to low pressure • Water runs downhill by gravity

2019 IAQA Annual Meeting Basic Rule of Water Damage No. 4

• Water runs downhill by gravity (i.e., roof and flashing leaks, attic condensation)

2019 IAQA Annual Meeting Five Forces of Rainwater Penetration • Gravity • Surface Tension • Capillary Action • Momentum (Kinetic Energy) • Air Pressure Differences

2019 IAQA Annual Meeting 2019 IAQA Annual Meeting Which forces of drainage are shown?

1. Drip 2. Stucco Cracks 3. Failed vent cover Edge Gravity Surface Tension QUIZ Capillary Action Question Momentum (Kinetic Energy) Air Pressure Differences 2019 IAQA Annual Meeting Four Strategies to Prevent Rainwater Penetration: 4 D’s

• Deflection • Drainage • Drying • Durable Materials

Stave Church at Urnes, Norway – Norway’s oldest stave church that dates back to the early 12th century in its present form. Wooden components of an even older church were used to build it. 2019 IAQA Annual Meeting Deflection • Deflection is the first • This part of a building principal in water system sheds water management. away from roofing and • The intent is to keep rain siding finishes, as well off the building façade as any sheathing panels and minimize penetration or water resistant of the building envelope membranes. • Pitched roofs, deep eaves or overhangs that deflect water away from the walls, proper flashing around windows and doors, and sealants applied to penetrations and joints 2019 IAQA Annual Meeting 2019 IAQA Annual Meeting What do these homes share in common?

QUIZ Question 2019 IAQA Annual Meeting Outside New: Surface water drainage

• Poor drainage & high water table conditions threaten slab-on-grade homes • Landscape irrigation and water reuse programs can exacerbate drainage problems • This phenomenon is known as “Damp Rising”

Developer discretion 2019 IAQA Annual Meeting 2019 IAQA Annual Meeting 2019 IAQA Annual Meeting Drainage • This part of a building system sheds water away from roofing and siding finishes, as well as any sheathing panels or water resistant membranes. Diagram from J.F. Straube, Ph.D., PE • Pitched roofs, deep eaves or overhangs that deflect water away from the walls, proper flashing around windows and doors, and sealants applied to penetrations and joints 2019 IAQA Annual Meeting Wood Materials Exposed to Moisture

2019 IAQA Annual Meeting Solid Pine: Repeated Wetting and Drying

2019 IAQA Annual Meeting Exterior Grade Plywood: Repeated Wetting and Drying

2019 IAQA Annual Meeting OSB: Repeated Wetting and Drying

2019 IAQA Annual Meeting Bad Marriage Case History 5417

Owners of newly purchased home experience musty odors and respiratory irritation. Examination of home reveals no apparent plumbing leaks or water infiltration from irrigation sources. Windows reveal exterior separation of drainage plane and burglar installation methods that breach the window sill drainage plane. 2019 IAQA Annual Meeting Bad Marriage Case History 8209 Water damage and microbial growth were observed in first floor Kitchen window Water damage was beneath windows on both first and second floors Aluminum windows were positioned inset from the exterior drainage plane to give the appearance of a CMU wall Second floor windows were installed without flashing. Repair required replacement of all windows on second floor

Original window installation (face 2019 IAQA Annual Meeting seal) converted to concealed barrier Paint • Moisture penetrates the exterior wall in both directions • In the heating season, water vapor moves inside to outside • In the cooling season, water vapor moves from outside to inside • When is the temperature gradient most severe?

2019 IAQA Annual Meeting Permeance Ratings*

• Vapor impermeable: 0.1 perm or less (Class 1) • Vapor semi-impermeable: 1.0 perm or less and > than 0.1 perm (vapor retarder) (Class II) • Vapor semi-permeable: 10 perms or less and > 1 perm (Class III) • Vapor permeable: > than 10 perms

“Perm” is a unit of measurement used to characterize permeability

2019 IAQA Annual Meeting General Classes of Permeance Impermeable Vapor semi-permeable • Rubber membranes • Plywood • Polyethylene film • Bitumen impregnated Kraft paper • Glass • OSB • Aluminum foil • Elastomeric paints • Foil-faced insulated • Most latex-based sheathing paints • Vapor semi-impermeable Permeable • Oil-based paints • Unpainted gypsum board and plaster • Vinyl wall coverings • Some latex-based paints • Housewraps 2019 IAQA Annual Meeting Caulking CAULK TYPES • Choosing the right caulk • High performance silicone requires an understanding of its • Polyurethane limitations • Polysulphide • Movement capacity is • Thermo-plastic one of the most important elastomeric factors when selecting a caulking product, • Acetoxy silicones especially if the joint • Mildew resistant moves in response to • Acrylic solar heating, changes in moisture or structural • Butyl movement • Acoustical • UV light resistance, • Oil-based compatibility, life expectancy, joint design also affect this decision2019 IAQA Annual Meeting Low Movement Caulking Medium Movement Caulking Application: Slight or infrequent joint movement Application: slow moving Types: bituminous rubber, joints i.e., masonry control oleoresinous and butyl joints rubber Types: Plasto-elastic Restrictions: should not be caulking including acrylic applied to joints in constant latex, acrylic solvent and movement cycles or large butyl and thermoplastic deflections and protected elastomerics (kreytons) from the weather Maximum Joint Movement: Maximum Joint Movement: below 25% of joint width below 5% of the joint width Service life: 5-15 years for Service life: 2-5 years when plasto-elastic and 1 used in exposed exterior 10-20 years for elasto- applications plastic material

2019 IAQA Annual Meeting Improper application of Bituminous sealant on medium To high movement joint, Orlando

Mark Meshulam, Chicago Window Expert, Window Sealant Failure 2019 IAQA Annual Meeting High Movement Caulking

Application: Large or fast moving joints between metals and window frames Types: One and two part polyurethanes, acetoxy and neutral cure silicones Service Life: 10-25 years

2019 IAQA Annual Meeting Caulking Use Summary

Caulking Durability Application Comments Low Movement Low Suitable when low movement is Butyl rubber Caulking expected Synthetic rubber Oil based Medium High Indoor application suitable for Acrylic latex Movement small joints with limited Thermoplastic Caulking movement elastomerics High Neutral cure Movement High Suitable for indoor and outdoor silicones Caulking applications Acetoxy silicone Long service life expected Polyurethanes Polysulphides

Air Leakage Control Manual, Existing Multi-Unit Residential Buildings, CMHC, 2007 2019 IAQA Annual Meeting 1. Face-Sealed Barrier Walls • Face-sealed walls are • Relatively low costs encourage face-sealed essentially impermeable to construction; however, on- water and air going maintenance will be costly • The surface is exposed to Examples extreme temperatures and • Stucco on block solar radiation that impose • EIFS stress on joints between cladding and other • Log cabins components • Sealant durability is diminished requiring regular maintenance and replacement

2019 IAQA Annual Meeting 2. Drainage Cavity Wall • Drainage cavity represents a typical brick veneer wall and many cladding systems that use stone or metal panels • Drain holes serve as vents and protect against water penetration by capillarity, surface tension and gravity • This strategy is intended to collect and control rainwater that passes through the exterior cladding 2019 IAQA Annual Meeting 3. Internal Drainage Plane Wall • This is common with stucco applications that use building paper or a non perforated building wrap as a water barrier. • A drainage screed is located at the base to increase drainage and improve drying

2019 IAQA Annual Meeting 2019 IAQA Annual Meeting Drainage Plane: Stucco Cracking

• Stucco systems vary in construction sequence • 3 layer (scratch, brown, final) requires uniform application of wire mesh • Stucco must not dry too quickly • Intimate contact between the stucco and drainage plane allows penetration • Corrosive substances threaten the wire mesh in stucco Construction Skill Level

2019 IAQA Annual Meeting 4. Pressure-Equalized Rain-Screen Wall • A pressure-equalized rain screen (PER) is a drainage cavity wall that is designed so that the air pressure behind the cladding is similar to the exterior pressure. • This strategy is commonly used metal and glass curtain walls.

Weeped and Pressure- 2019 IAQA Annual Meeting Vented Equalized Pressure-Equalized Rain Screen

• Rainscreen systems allow air to flow into the base and out the top • Water that enters the system is removed by ventilation and by gravity down the rear face 2019 IAQA Annual Meeting Western Red Cedar Siding: Cooler Climates

• This wall assembly is well suited to high interior humidity • Water vapor migrates through the wall assembly from the warm interior to cold exterior: note the location of the vapor barrier

2019 IAQA Annual Meeting Face Seal/Barrier-Type Systems: Problems

• Ineffective exterior seals from improper installation or ageing of materials • Odd shaped, custom or EIFS windows are often sealed to form a barrier against water penetration

2019 IAQA Annual Meeting Water Penetration Resistance Strategy: 2. Drainage • This strategy assumes water penetration will occur through the primary exterior glazing seal and joints of the window assembly; however, its design collects the water and directs it to the exterior • This is a preferred strategy because the design is redundant and is not dependent on exterior seal maintenance because water penetration is assumed to occur “Water Penetration Resistance of Windows,” Canadian Mortgage and Housing2019 IAQA Annual Meeting Corporation Commercial Windows

• Weep holes that were used, blocked or drilled?

2019 IAQA Annual Meeting Drainage: Problems • Interior water penetration from poorly functioning internal system seals or water overflowing horizontal members, such as sills. • Sill members should be designed to accommodate anticipated water height within the system, which is based on design wind pressures. • Defects may also contribute to interior leakage.

2019 IAQA Annual Meeting Water Penetration Resistance Strategy: 3. Concealed Barrier • Exterior surface and • This design joints of windows are strategy accepts sealed or the curtain wall the idea that some is sealed permanently to water may pass prevent water penetration behind the face of the window (or • This strategy uses cladding). These exterior gaskets and windows and walls sealants incorporate a • Failure results in water drainage plane accumulation within the within the window framing and penetration (or wall) assembly. into the building 2019 IAQA Annual Meeting Water Penetration Resistance Strategy: Concealed Barrier • Strategy for rain penetration where the water shedding surface is behind the cladding rather than the exterior moisture barrier

2019 IAQA Annual Meeting Water Penetration Resistance Strategy: Improved Concealed Barrier

2019 IAQA Annual Meeting Water Penetration Resistance Strategy: 4. Rain Screen/Curtain Window • Curtain Wall/Window: Typically used for high performance aluminum framed wall systems. • Less condensation; cavity breathes and dries • Outer panel purely esthetic

2019 IAQA Annual Meeting Rain Screen/Curtain Wall: Problems • The lack of a sealant can pose challenges • There may be a lack of responsibility for water penetration between the manufacturer and installer • The A/E’s depth of knowledge may be limited

R. Keleher, AIA CSI LEED, Rainscreen Cladding Systems, North Clad Rainscreen Solutions, 2009 2019 IAQA Annual Meeting Residential Foundations: Basement, Crawl Space, Pier Foundation, Concrete Slab

2019 IAQA Annual Meeting Basement Foundation • Common throughout the country • IAQA Investigation • Built using concrete perimeter of Perspective pillars that support structure Finished Basements • Usually dug to a minimum depth of • Obscured identification of 8 feet leaks • Pros: added space, storage, natural • May contribute to air quality ventilation, cooling mechanism concerns • Cons: Cost, moisture penetration, Unfinished Basements mold, often attains dew point • Easy identification of leaks temperatures above and adjacent to basement • Facilitates access to repair

plumbing leaks2019 IAQA Annual Meeting Crawlspace Foundation • Three to four feet high and are used when water table conditions are high or soils are difficult to dig • Supported by concrete pillars or poured wall systems • Pros: Best for high water take conditions, may facilitate cooling in summer • Cons: Heat sink in winter, prone the moisture accumulation when poorly ventilated, may accumulate water, should be sealed 2019 IAQA Annual Meeting Pier and Beam Foundation • Constructed using circular or square pads of concrete positioned around the outer perimeter. • The pads are inserted and secured into the ground with treated lumber or steel rods • Pros: Ideal where a traditional foundation may not be possible • Cons: may leak to creaking and sagging floors as well as issues of poor ventilation

2019 IAQA Annual Meeting Concrete Slab Foundation • Most common foundation • Slabs are four to eight inches thick and reinforced with steel rods • Pros: Inexpensive and quick foundation to build, no air space beneath • Cons: difficult to repair plumbing leaks, limited protection from flooding, absorbent

2019 IAQA Annual Meeting What is the reoccurring theme of this presentation?

A. All components of drainage plane are in motion QUIZ Question B. Buildings that integrate materials that move together . . . will last longer

C. The most important attribute of a building is to keep it dry

D. The principles of effective construction have been known for centuries

E. Air quality consulting requires a comprehensive understanding of building construction and moisture management

2019 IAQA Annual Meeting Questions?

Ralph Moon [email protected]

2019 IAQA Annual Meeting